Living radical polymerization grafting from

A dense polymer brush is obtained using the grafting from techniques. Surface-initiated polymerization in conjunction with a living polymerization technique is one of the most useful synthetic routes for the precise design and functionalization of the surfaces of various solid materials with well-defined polymers and copolymers. Above all, surface-initiated living radical polymerization (LRP) is particularly promising due to its simplicity and versatility and it has been applied for the synthesis of Au NPs. 

The metal-catalyzed copolymerization from carbon-halogen bonds in the main chain can be employed widely for graft polymer synthesis. A combination of nitroxide-mediated and copper-catalyzed living radical polymerizations, for example, gives graft copolymers G-6, where the main chain is prepared by the former.432 The chlorobenzyl unit in the copolymer is not active during the polymerization but, upon copper catalysis, it can initiate living radical polymerizations of styrene and methacrylates. 

Keywords Controlled/living radical polymerization Core-shell particle Dispersion polymerization Emulsion polymerization Grafting from Hybrid Miniemulsion polymerization Nanogel Nanoparticle... 

Initiators for the controlled living radical polymerization could also be introduced to silica particles. Nitroxide-mediated polymerization (NMP) conducted with styrene in miniemulsion led to the generation of core-shell particles, with styrene grafted to the central silica particle [131]. PBA could be polymerized from 20 nm silica beads by attaching an ATRP agent to the silica surface and subsequent miniemulsion polymerization [132]. Confining the polymerization to miniemulsion droplets could avoid gel formation, which was observed in the bulk reaction. Due to the limited monomer diffusion, only 25-35% of conversion could be obtained in bulk. 

In recent years, focus has moved to the use of living radical polymerization techniques such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) for the production of well-defined polymer coatings. Both the grafting from and grafting to approaches have been explored for the attachment of MPC-based polymers onto a variety of substrates. Grafting from requires the incorporation of initiator sites onto the biomaterial surface prior to the polymerization reaction. This usually involves a series of... 

SCHEME 8.5 Functionalization of polymeric membranes via (a) surface-initiated con-trolled/living radical polymerization (CRP) ( grafting from approach) and (b) surface click reactions ( grafting to approach). Reprinted with permission from Reference 129. Copyright 2009 American Chemical Society. 

Chunhua Liu. Grafting polymers from the surface of silica nanoparticles via living radical polymerization and their applications. Hefei University of Science and Technology of China, 2009. 

Zoppe, J., Habibi, Y., Rojas, O.J., Venditti, R.A., Johansson, L.-S., Efimenko, K., Osterberg, M., Laine, J. 2010. Poly(N-lsopropylacrylamide) Brushes Grafted from Cellulose Nanocrystals via Surface-Initiated Single-Electron Transfer Living Radical Polymerization. Biomacromolecules 11 2683-2691. 

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